The potential role of hybridization in diversification and speciation in an insular plant lineage: insights from synthetic interspecific hybrids. Issue 5 (1st September 2017)

• Record Type: Journal Article
• Authors: Kerbs, Benjamin; Ressler, Jacob; Kelly, John K; Mort, Mark E; Santos-Guerra, Arnoldo; Gibson, Matthew J S; Caujapé-Castells, Juli; Crawford, Daniel J
• Editors: Hiscock, Simon J
• Is Part Of: AoB plants. Volume 9:Issue 5(2017)
• Publication Date: 2017-09-01
• Subjects: Canary Islands -- phenotypic groups -- synthetic hybrids -- transgressive traits; Plants -- Periodicals; Botany -- Periodicals; 580.5
• DOI: 10.1093/aobpla/plx043
• Languages: English
• ISSNs: 2041-2851

Abstract

Abstract : Islands contain some of the most remarkable yet imperiled plants anywhere on Earth. Despite remarkable ecological/morphological diversity, insular endemics often retain the ability to hybridize and produce vigorous, fertile progeny. This study over several generations of synthetic interspecific hybrids between two species endemic to the Canary Islands shows that gene exchange between species can produce novel traits, transgressive phenotypes and novel combinations of features not seen in their parents. Results of this study provide experimental evidence of the potential of hybridization to promote diversification and possibly generate stabilized hybrid derivatives in plants in an oceanic archipelago. Abstract: Hybridization is recognized as an important process in plant evolution, and this may be particularly true for island plants where several biotic and abiotic factors facilitate interspecific hybridization. Although rarely done, experimental studies could provide insights into the potential of natural hybridization to generate diversity when species come into contact in the dynamic island setting. The potential of hybridization to generate morphological variation was analysed within and among 12 families (inbred lines) of an F4 hybrid generation between two species of Tolpis endemic to the Canary Islands. Combinations of characters not seen in the parents were present in hybrids. Several floral and vegetative characters were transgressive relative to their parents. Morphometric studies of floral, vegetative and fruit characters revealed that several F4 families were phenotypically distinct from other families, and from their parents. The study demonstrates that morphologically distinct pollen-fertile lines, potentially worthy of taxonomic recognition if occurring in nature, can be generated in four generations. The ability of the hybrid lines to set self-seed would reduce gene flow among the lines, and among the hybrids and their parental species. Selfing would also facilitate the fixation of characters within each of the lines. Overall, the results show the considerable potential of hybridization for generating diversity and distinct phenotypes in island lineages.